“Runflat” tire inserts are devices that allow vehicles to continue operation after one or more pneumatic tires have been deflated. The inserts are installed snugly against the wheel and within a tire mounted on the wheel to keep the deflated tire stable and/or to distribute load on the wheel while keeping the wheel rims off the ground, preventing rim damage while substantially maintaining mobility and control. While most tire inserts have limited range at speed, they are typically designed to allow the vehicle on which they are installed to get far enough away from the point at which deflation occurred to get help or at least get out of danger. Additionally, some tire inserts can redirect explosive forces to reduce damage to a vehicle should it drive over an explosive device, such as a land mine or the like. Inserts improperly installed are more likely to fail during deflated tire operation or even during normal operation of the vehicle on which the wheel is installed. Proper installation is thus very important to the proper function runflat tire inserts, but because of their structure and where they are located, proper installation can be difficult and time consuming.
A typical runflat tire insert for single piece wheels is substantially toroidal and has at least one break therein to allow the inserts to be slipped onto a wheel. Some inserts have two or more sections separated by breaks, while others have one section that stretches open at a single break. In all of these incarnations, the sections of the insert must be connected and drawn together over the break(s) by attachment apparatus to ensure that the insert stays in its designated configuration. Because the inserts are installed in the tire cavity, they must be installed after at least partial tire installation, hindering access to the insert and attachment apparatus. The difficulty associated with insert installation, then, arises from maneuvering parts and tools around, under, and within the tire. To add to these difficulties, the various designs of attachment apparatus that have been employed in tire inserts sometimes require that mating insert components be manufactured with very tight tolerances to insure proper assembly and function at normal rotational speeds of wheels.
An example of a prior art solution is shown in U.S. Pat. No. 5,626,696, which incorporates a screw and nut turn buckle type connection between two half rings of the device. However, other prior art apparatus, such as those of U.S. Pat. Nos. 4,270,592 and 3,976,114, incorporate combinations of positional retaining member “hook and ratchet” or “plug and socket” arrangements. These combinations typically require separate engagement and disengagement devices to activate the fasteners. Additional prior art apparatus are shown, for example, in U.S. Pat. No. 4,393,911, which employs axial bolting members with limited adjustability, and in U.S. Pat. No. 4,391,317, which uses circumferential bolting members that are difficult to access inside of tire cavities. All of these prior art solutions still suffer from cumbersome, laborious installation and, in some cases, parts that must be installed from outside the wheel/tire/insert assembly. There is thus a need for an attachment apparatus that allows easier access and operation to speed and ease the installation process for inserts There is also a need for tire inserts that eliminate separate components to accomplish such installation.
Embodiments comprise a new attachment apparatus used in assembling, adjusting, and disassembling runflat tire inserts that includes all parts required for proper installation. Embodiments include an actuator more easily accessed from outside the tire and more easily operated by virtue of its orientation and construction. The actuator comprises a nut, bolt head, or the like accessible with a tool when a tire is mounted on the wheel for work with the inserts. The actuator can be attached to a mechanical assembly that converts rotation of the head into motion of parts of the insert toward or away from each other, depending on the direction of actuator rotation. For example, a gear and/or pinion can be used in the actuator. A preferred embodiment employs a worm and a pinion mounted in one part of an insert and a pin or the like, such as an eyebolt, mounted in another part with its shaft protruding toward the first half. Threads on the shaft of the eyebolt in preferred embodiments engage the pinion, such as via corresponding threads on the pinion's internal surface. The worm can be turned to rotate the pinion, which moves the bolt along its axis via the threads, which moves the parts of the insert together or apart, depending on which direction the worm is rotated. Other embodiments employ a rack and pinion arrangement and a threaded anchor. Embodiments can also include a locking feature to ensure that the actuator is fixed in position once assembly is complete.